Capsule endoscope and manufacturing method thereof

ABSTRACT

A fitting section at which a cylindrical cover is fitted into a transparent cover, the cylindrical cover containing therein a CCD imager, and the transparent cover making visible light from a subject incident on the CCD imager, and being formed of a member transmitting laser light, is irradiated with laser light from the outside of an endoscope casing, thereby welding the cylindrical cover and the transparent cover together.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT Application No.PCT/JP2006/325245, filed Dec. 19, 2006, which was published under PCTArticle 21(2) in Japanese.

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2005-365209, filed Dec. 19, 2005,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a small-sized capsule endoscope formedinto a capsule-shape used for inspection or the like inside a livingbody, and a method of manufacturing the same.

2. Description of the Related Art

Techniques related to capsule endoscopes are disclosed in, for example,Jpn. Pat. Appln. KOKAI Publication No. 2001-91860 (paragraph No.[0012]), Jpn. Pat. Appln. KOKAI Publication No. 2004-65575 (paragraphNos. [0028], [0071]), and Jpn. Pat. Appln. KOKAI Publication No.2005-261504 (paragraph No. [0033]). In Jpn. Pat. Appln. KOKAIPublication No. 2001-91860, that a capsule endoscope includes anexterior case in which a circuit board and the like are encased in awatertight state, the exterior case is constituted of a substantiallyhemispheric transparent cover covering the front of an objective lens,and a cylindrical cover covering the rear of the objective lens andhaving a hemispheric shape at a rear end thereof, and the transparentcover and the cylindrical cover are bonded to each other in a watertightstate, thereby forming a capsule endoscope is disclosed.

In Jpn. Pat. Appln. KOKAI Publication No. 2004-65575, that a capsuleendoscope includes a capsule container sealed by using a front-end coverand a rear-end cover, an O-ring for watertight sealing is interposedbetween an outer circumferential surface of the main body and an innercircumferential surface of the rear cover, and the front-end coverconstituted of a flexible material and the main body are fixed to eachother by using an adhesive that can secure watertightness even when itis subjected to elastic deformation is disclosed.

In Jpn. Pat. Appln. KOKAI Publication No. 2005-261504, that anobservation side cover and a capsule main body are fixed to each otherby welding so as to be integral with each other by means of ultrasonicheat generation achieved by applying ultrasonic vibration to the coverand the main body is disclosed.

Pat. Document 1: Jpn. Pat. Appln. KOKAI Publication No. 2001-91860(paragraph No. [0012])

Pat. Document 2: Jpn. Pat. Appln. KOKAI Publication No. 2004-65575(paragraph No. [0028], [0071])

Pat. Document 3: Jpn. Pat. Appln. KOKAI Publication No. 2005-261504(paragraph No. [0033])

BRIEF SUMMARY OF THE INVENTION

In the techniques disclosed in Jpn. Pat. Appln. KOKAI Publication No.2001-91860 and Jpn. Pat. Appln. KOKAI Publication No. 2004-65575, forexample, when the transparent cover and the cylindrical cover are bondedto each other, it is difficult to achieve separation with constantapplication amount of adhesive. Further, in the technique disclosed inthe above patent documents, when the transparent cover and thecylindrical cover are bonded to each other, an excessive amount ofadhesive is applied to the outer surface of the capsule main body. Anuneven part or a burr-like part is formed by the adhesive on the outersurface of the capsule main body in some cases. If such an uneven partor a burr-like part is formed, according to the above patent documents,complicated post-treatment process work must be performed in order tofinish the outer surface of the capsule main body smooth.

The capsule endoscope is swallowed into a body of a person such as apatient, is used to inspect the inside of the living body, and issmall-sized. It is undesirable for such a small-sized capsule endoscopethat an uneven part or a burr-like part is formed at, for example, abonded part at which the transparent cover and the cylindrical cover arebonded to each other. It is therefore necessary for the small-sizedcapsule endoscope that the bonding should be reliably performed with theouter surface of the capsule main body finished smooth.

The technique disclosed in Jpn. Pat. Appln. KOKAI Publication No.2005-261504 can solve the problems of the above patent documents.However, in the technique of Jpn. Pat. Appln. KOKAI Publication No.2005-261504, an ultrasonic horn is brought into contact with theobservation side cover and the capsule main body, and an ultrasonic waveis oscillated. Therefore, there is the possibility of electroniccomponents and the like contained in the capsule main body beingadversely affected.

In the technique of Jpn. Pat. Appln. KOKAI Publication No. 2005-261504,the ultrasonic horn is brought into contact with the cover and thecapsule main body, and hence a surface of a part of the resin which isbrought into contact with the horn is heated. Thus, by the technique ofthe above patent document, the surface is roughened, and no smoothcapsule outer surface can be obtained. Further, using the technique ofthe above patent document, it is difficult to achieve, for example,narrow and linear adhesion in the ultrasonic welding.

Besides the above problem, in order to bring the ultrasonic horn intocontact with the observation side cover or the capsule main body, andeffectively transmit the ultrasonic wave, there is the necessity toprovide a notch or the like in the part of the cover or the capsule mainbody at which the ultrasonic horn is brought into contact with the coveror the capsule main body.

An object of the present invention is to provide a capsule endoscope inwhich welding and bonding can be securely performed by irradiation oflaser light, and a method of manufacturing the capsule endoscope.

According to a first aspect of the present invention, there is provideda capsule endoscope comprising: a first exterior member formed of anoptical resin member transmitting visible light and laser light; and asecond exterior member which is arranged with respect to the firstexterior member in such a manner that the second exterior member isbrought into surface contact with the first exterior member, and isformed of a resin member containing a laser light absorbing agent,characterized in that laser light is applied to the second exteriormember through the first exterior member, thereby melting the secondexterior member, and the first exterior member and the second exteriormember are bonded to each other by laser welding.

According to a second aspect of the present invention, a capsuleendoscope comprising: a first exterior member formed of an optical resinmember transmitting visible light and laser light; a second exteriormember which is arranged with respect to the first exterior member insuch a manner that the second exterior member is brought into surfacecontact with the first exterior member, and is formed of a resin member;and a laser light absorbing member provided at a part at which the firstexterior member and the second exterior member are in surface contactwith each other, characterized in that laser light is applied to thelaser light absorbing member through the first exterior member, therebymelting the laser light absorbing member, and the first exterior memberand the second exterior member are bonded to each other by laserwelding.

According to a third aspect of the present invention, a method ofmanufacturing a capsule endoscope characterized by comprising: arranginga second exterior member formed of a resin member containing a laserlight absorbing agent with respect to a first exterior member formed ofan optical resin member transmitting visible light and laser light insuch a manner that the second exterior member is brought into surfacecontact with the first exterior member; and applying laser light to thesecond exterior member through the first exterior member, therebymelting the second exterior member, and bonding the first exteriormember and the second exterior member to each other by laser welding.

According to a fourth aspect of the present invention, a method ofmanufacturing a capsule endoscope characterized by comprising: arranginga second exterior member formed of a resin member with respect to afirst exterior member formed of an optical resin member transmittingvisible light and laser light in such a manner that the second exteriormember is brought into surface contact with the first exterior member;providing a laser light absorbing member at a part at which the firstexterior member and the second exterior member are in surface contactwith each other; and applying laser light to the laser light absorbingmember through the first exterior member, thereby melting the laserlight absorbing member, and bonding the first exterior member and thesecond exterior member to each other by laser welding.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 shows the configuration of a capsule endoscope according to afirst embodiment of the present invention.

FIG. 2 shows the configuration of a capsule endoscope according to asecond embodiment of the present invention.

FIG. 3 shows the configuration of a front-end section of a capsuleendoscope according to a third embodiment of the present invention.

FIG. 4 shows the configuration of a front-end section of a capsuleendoscope according to a fourth embodiment of the present invention.

FIG. 5 shows the configuration of a front-end section of an endoscopeaccording to a fifth embodiment of the present invention.

FIG. 6 shows the configuration of a front end of an insertion section ofan electronic endoscope according to a sixth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of the present invention will be described below withreference to the accompanying drawings.

FIG. 1 shows a configuration view of a capsule endoscope. The capsuleendoscope 1 is provided with a cylindrical cover 2 serving as a secondexterior member, and a transparent cover 3 serving as a first exteriormember. The cylindrical cover 2 and the transparent cover 3 are fittedto each other, thereby forming an integrated cylindrical capsuleendoscope casing 4.

The cylindrical cover 2 is formed into a cylindrical shape. In thecylindrical cover 2, a circular first opening end section 2 a is formedat one end part, and a hemispheric section 2 b is formed at the otherend part. The cylindrical cover 2 is formed of a resin member containinga laser light absorbing agent. That is, the cylindrical cover 2 isformed of a thermoplastic resin member which is a nontransparent resinmember transmitting no laser light, and absorbs laser light (laserbeam).

Types of the nontransparent resin member of the cylindrical cover 2transmitting no laser light include, for example, polycarbonate (PC),ABC resin (ABC), polysulfone (PSU), polyphenylsulfone (PPSU),polyphenyleneoxide (PPO), polyphenylenesulfide (PPS), styrene resin,polyamide (PA) such as nylon 6 (PA6) and nylon 66 (PA66), polyethylene(PE), polypropylene (PP) and styrene-acrylonitrile copolymer, and thelike, each of which is mixed with a predetermined coloring agent such ascarbon black. Incidentally, the nontransparent resin member may bemechanically strengthened by glass fiber or the like as the need arises.

Further, a coloring member is added to the cylindrical cover 2. As aresult, when the cylindrical cover 2 is melted by irradiation of laserlight, the color of the cover 2 is changed by the coloring member.Examples of the coloring member include titanium white, TiO₂, a pigment(cyanine series), and the like.

The transparent cover 3 is formed into a hemispheric shape. A circularsecond opening end section 3 a is formed at one end part of thetransparent cover 3. The transparent cover 3 is formed of an opticalresin member that transmits visible light and laser light. That is, thetransparent cover 3 transmits white illuminating light, and transmits,for example, reflected light from a body cavity. The transparent cover 3is formed of a light-transmitting resin member that transmits visiblelight, for example, 70% or more. Further, the transparent cover 3 isformed of a member which is a light-transmitting resin member havingthermoplasticity. The light-transmitting resin member of the transparentcover 3 is not particularly limited as long as it is a member thattransmits laser light at a predetermined transmissivity or more.

Types of the light-transmitting resin member include, for example,polycarbonate (PC), acrylic resin, cycloolefin polymer (COP),polyurethane (PU), styrene resin, and polyamide (PA) such as nylon 6(PA6) and nylon 66 (PA66).

In the cylindrical cover 2, a CCD imager 5 serving as an image pickupdevice, a signal processing circuit 6, a communication processingcircuit 7, a plurality of button-shaped batteries 8, and an antenna 9are contained. Assuming that the transparent cover 3 side of the CCDimager 5 is the front side, the signal processing circuit 6, thecommunication processing circuit 7, the plural button-shaped batteries8, and the antenna 9 are provided in the order mentioned from the rearside of the CCD imager 5.

An objective optical system 10 is provided on the transparent cover 3side of the CCD imager 5. The objective optical system 10 forms light ofan optical image transmitted through the transparent cover 3 andincident thereon into an image. The objective optical system 10 includesan objective lens 11, and an optical lens arranged in a lens frame 12.The CCD imager 5 is provided at an image formation position of theobjective optical system 10. Further, around the objective opticalsystem 10, a plurality of, for example, four white LEDs 13 are providedin the same plane as an illumination optical system. Incidentally, theobjective optical system 10 and the white LEDs 13 are provided in aplane 5 a on the transparent cover 3 side of, for example, the CCDimager 5.

The signal processing circuit 6 includes a circuit for emission-drivingthe white LEDs 13, a circuit for driving the CCD imager 5, and a circuitfor forming an image pickup signal output from the CCD imager 5 into animage signal.

The communication processing circuit 7 transmits an image signal formedby the signal processing circuit 6 to an external apparatus as anelectric wave.

The number of button-shaped batteries provided is, for example, three.These button-shaped batteries 8 supply power to the CCD imager 5, thesignal processing circuit 6, the communication processing circuit 7, andthe like.

The antenna 9 is provided in a hemispheric space formed by thehemispheric section 2 b of the cylindrical cover 2. The antenna 9 iselectrically connected to the communication processing circuit 7, andradiates a signal processed by the communication processing circuit 7 asan electric wave.

In the cylindrical cover 2 and the transparent cover 3, the firstopening end section 2 a of the cylindrical cover 2 is fitted into thesecond opening end section 3 a of the transparent cover 3, therebyintegrating the cylindrical cover 2 and the transparent cover 3 witheach other. The first opening end section 2 a is formed by providing astep 2 c on the entire circumference on the outer surface side of thecylindrical cover 2. The second opening end section 3 a is formed byproviding a step 3 b on the entire circumference on the inner surfaceside of the transparent cover 3.

However, the first opening end section 2 a of the cylindrical cover 2 isinserted into the second opening end section 3 a of the transparentcover 3, the second opening end section 3 a being on the outside, andthe first opening end section 2 a being on the inside, thereby achievingthe fit of the covers 2 and 3. In other words, the covers 2 and 3 are ina state where the transparent cover 3 covers the outer surface of thecylindrical cover 2.

This fitting section 14 includes a boundary surface 15 at which thesecond opening end section 3 a and the first opening end section 2 a arein surface contact with each other. The boundary surface is formedconcentric with the side surface of the cylindrical capsule endoscopecasing 4. Incidentally, a distal end part of the second opening endsection 3 a is hit against the step 2 c of the cylindrical cover 2, andforms a hitting surface 16.

A laser welding section 17 is formed on the entire circumference of thecylindrical boundary surface 15. At the laser welding section 17, thefirst opening end section 2 a and the second opening end section 3 a aretightly and integrally bonded to each other in a watertight state by thewelding caused by external irradiation of laser light Q.

That is, the laser light Q is transmitted through the second opening endsection 3 a of the transparent cover 3, and is applied to the firstopening end section 2 a of the cylindrical cover 2 formed of thethermoplastic resin member. The irradiation direction of the laser lightQ is a direction substantially perpendicular to the transparent cover 3,i.e., a direction substantially perpendicular to the side surface of thecapsule endoscope casing 4. In this case, the laser light Q is appliedto the entire circumference of the side surface of the capsule endoscopecasing 4 while the capsule endoscope casing 4 is rotated. Alternatively,the laser light Q is applied to the entire circumference of the sidesurface of the capsule endoscope casing 4 while the irradiationdirection of the laser light Q is changed.

The laser light Q is transmitted through the transparent cover 3, and isapplied to the cylindrical cover 2. As a result of this, the firstopening end section 2 a of the cylindrical cover 2 is heated and melted.Thus, the first opening end section 2 a and the second opening endsection 3 a are thermally welded, i.e., the transparent cover 3 and thecylindrical cover 2 are welded together.

The laser light Q has such a wavelength that a predeterminedtransmissivity or more, for example, 26% or more can be obtained withrespect to the transparent cover 3. As a result of this, when the laserlight Q is transmitted through the transparent cover 3 formed of thelight-transmitting resin member, the energy loss of the laser light Q isreduced.

As a result, the boundary surface 15 between the second opening endsection 3 a formed of the light-transmitting resin member and the firstopening end section 2 a formed of the thermoplastic resin member isirradiated with laser light Q with less energy loss. By the irradiationof the laser light Q, energy sufficient to heat and melt the boundarysurface 15 is accumulated in the boundary surface 15. Thus, sufficientheating and melting take place at the boundary surface 15 and,thereafter the second opening end section 3 a and the first opening endsection 2 a are welded together. That is, the cylindrical cover 2 andthe transparent cover 3 are welded together by the laser welding section17.

Further, a coloring member is added to the cylindrical cover 2. As aresult, when the cylindrical cover 2 is melted by the irradiation oflaser light, the color of the cover 2 is changed by the coloring member.However, when the cylindrical cover 2 and the transparent cover 3 arewelded together by the laser welding section 17, the fact that thewelding has been achieved can be confirmed by the change in colorappearing on the cylindrical cover 2.

A protection member 18 is provided at the fitting section at which thefirst opening end section 2 a is fitted into the second opening endsection 3 a. More specifically, the protection member 18 is provided onthe entire circumference of the inner circumferential surface of thefirst opening end section 2 a. The protection member 18 is provided onthe entire circumference of the outer circumferential surface of the CCDimager 5. Incidentally, it is sufficient if the protection member 18 isprovided on one of or both of the entire circumference of the innercircumferential surface of the first opening end section 2 a, and theentire circumference of the outer circumferential surface of the CCDimager 5.

The protection member 18 absorbs the laser light Q applied to theboundary surface 15 between the second opening end section 3 a and thefirst opening end section 2 a. The protection member 18 absorbsscattered light produced when the laser light Q is applied. Theprotection member 18 is formed of, for example, a member such as ceramicexcellent in heat insulating properties and light blocking effect. Asdescribed above, the protection member 18 absorbs the laser light Q andthe scattered light thereof, and hence the CCD imager 5 and the like arenot adversely affected by the laser light Q and the scattered lightthereof.

As described above, according to the first embodiment, the capsuleendoscope 1 includes the cylindrical cover 2 in which the CCD imager 5is contained, and the transparent cover 3 which is formed of the membertransmitting laser light, and through which visible light from thesubject is made incident on the CCD imager 5, and the cylindrical cover2 and the transparent cover 3 are welded together by irradiating thefitting section 14 at which the cylindrical cover 2 is fitted into thetransparent cover 3 with the laser light Q from the outside of thecapsule endoscope casing 4. As a result of this, even in a small-sizedcapsule endoscope, the cylindrical cover 2 and the transparent cover 3can be reliably welded together, and no uneven part or burr-like part isformed on the outer surface of the capsule endoscope casing 4. The outersurface of the capsule endoscope casing 4 can therefore be maintainedsmooth. Furthermore, complicated post-treatment process work need not beperformed.

The protection member 18 absorbs the laser light Q and the scatteredlight thereof. As a result of this, the laser light Q and the scatteredlight do not adversely affect the CCD imager 5 and the like.

Incidentally, the first embodiment may be modified as follows. In thefirst embodiment, as described above, the cylindrical cover 2 is formedof a resin member containing a laser light absorbing agent. That is, thecylindrical cover 2 is formed of a thermoplastic resin member, which isa nontransparent resin member that does not transmit laser light, andabsorbs laser light. Further, when the laser light Q is transmittedthrough the transparent cover 3, and applied to the cylindrical cover 2,the cylindrical cover 2 is heated and melted, and the transparent cover3 and the cylindrical cover 2 are welded together. However, the presentinvention is not limited to this. In the first embodiment, a laser lightabsorbing member may be provided at the part at which the cylindricalcover 2 and the transparent cover 3 are in surface contact with eachother, and laser light Q may be applied through the transparent cover 3to the laser light absorbing member, thereby melting the laser lightabsorbing member, and bonding the cylindrical cover 2 and thetransparent cover 3 to each other by laser welding. The laser lightabsorbing member is formed of a thermoplastic resin member or anapplication agent that absorbs laser light. In this case, thecylindrical cover 2 need not contain a laser light absorbing agent.

Next, a second embodiment of the present invention will be describedbelow with reference to the accompanying drawings. Incidentally, thesame parts as those in FIG. 1 will be denoted by the same referencesymbols and detailed description of them will be omitted.

FIG. 2 shows a configuration view of a capsule endoscope. A cylindricalcover 2 and a transparent cover 3 are made integral with each other byfitting a second opening end section 21 of the transparent cover 3 intoa first opening end section 20 of the cylindrical cover 2. The firstopening end section 20 is formed into a cylindrical shape. The secondopening end section 21 is formed by providing a step 22 on the entirecircumference on the outer surface side of the transparent cover 3.

However, the second opening end section 21 of the transparent cover 3 isinserted into the first opening end section 20 of the cylindrical cover2, the first opening end section 20 being on the outside, and the secondopening end section 21 being on the inside, thereby achieving the fit ofthe covers 2 and 3. In other words, the covers 2 and 3 are in a statewhere the cylindrical cover 2 covers the outer surface of thetransparent cover 3. Further, a distal end part of the first opening endsection 20 of the cylindrical cover 2 is in a state where it is hitagainst the step 22 of the transparent cover 3.

A laser welding section 23 is formed at a part at which the distal endpart of the first opening end section 20 is hit against the step 22 ofthe transparent cover 3. That is, laser light Q is applied to the partat which the distal end part of the first opening end section 20 is hitagainst the step 22 of the transparent cover 3 in the same direction asthe side surface direction of the capsule endoscope casing 4. In thiscase too, the laser light Q is applied to the circumferential hittingpart while the capsule endoscope casing 4 is rotated. Alternatively, thelaser light Q is applied to the circumferential hitting part while theirradiation position of the laser light Q is changed.

When the laser light Q is transmitted through the transparent cover 3,and is applied to the cylindrical cover 2, the distal end part of thefirst opening end section 20 of the cylindrical cover 2 is heated andmelted. As a result of this, the transparent cover 3 and the cylindricalcover 2 are welded together.

As described above, according to the second embodiment, even when thelaser welding section 23 is formed at the part at which the distal endpart of the first opening end section 20 is hit against the step 22 ofthe transparent cover 3, the same effect as the first embodiment can beobtained. That is, even in a small-sized capsule endoscope, thecylindrical cover 2 and the transparent cover 3 can be reliably weldedtogether, and an uneven part or a burr-like part is not formed on theouter surface of the capsule endoscope casing 4. The outer surface ofthe capsule endoscope casing 4 can therefore be maintained smooth.Furthermore, complicated post-treatment process work need not beperformed.

Incidentally, in the second embodiment, a laser light absorbing membermay be provided at the part at which the cylindrical cover 2 and thetransparent cover 3 are in surface contact with each other, and laserlight Q may be applied to the cylindrical cover 2, thereby melting thelaser light absorbing member, and bonding the cylindrical cover 2 andthe transparent cover 3 to each other by laser welding. The laser lightabsorbing member is formed of a thermoplastic resin member or anapplication agent that absorbs laser light. In this case, thecylindrical cover 2 need not contain a laser light absorbing agent.

Next, a third embodiment of the present invention will be describedbelow with reference to the accompanying drawings.

FIG. 3 shows a configuration view of an endoscope distal end section ofa capsule endoscope. The endoscope distal end section 30 is a lightguide part of the endoscope. The endoscope distal end section 30 isprovided with a distal end constituent member 31 made of metal. Thedistal end constituent member 31 is provided with a hole 32 forattaching an illumination optical system. A light guide fiber bundle 33is inserted in the hole 32 for attaching an illumination optical system,and fixed thereto. The light guide fiber bundle 33 is formed of a glassmember. A pipe sleeve 34 is fixed to the light guide fiber bundle 33.The pipe sleeve 34 is formed of a thermoplastic resin member thatabsorbs laser light Q.

A cover glass 35 is inserted in a front end part of the hole 32 forattaching an illumination optical system. The cover glass 35 abuts onthe pipe sleeve 34 at its distal end in a state where it is inserted inthe hole 32 for attaching an illumination optical system. The coverglass 35 is formed of a light-transmitting resin member that transmitsvisible light and laser light Q.

A laser welding section 36 is formed at a part at which the cover glass35 abuts on the pipe sleeve 34. The laser welding section 36 tightly andintegrally bonds the cover glass 35 and the pipe sleeve 34 to eachother, and fixes them to each other by welding caused by beingirradiated with the laser light Q from outside. That is, the laser lightQ is applied from the outside of the cover glass 35. The laser light Qis transmitted through the cover glass 35, and is applied to theabutment part between the cover glass 35 and the pipe sleeve 34. As aresult of this, the cover glass 35 and the pipe sleeve 34 are heated andmelted, thereby welding the cover glass 35 and the pipe sleeve together.

As described above, according to the third embodiment, the laser light Qis transmitted through the cover glass 35, and is applied to theabutment part between the cover glass 35 and the pipe sleeve 34. As aresult of this, the cover glass 35 and the pipe sleeve 34 are heated andmelted, thereby welding the cover glass 35 and the pipe sleeve 34together. Thus, even in a small-sized endoscope distal end section, thecover glass 35 and the pipe sleeve 34 can be reliably welded together.

Next, a fourth embodiment of the present invention will be describedbelow with reference to the accompanying drawings. Incidentally, thesame parts as those in FIG. 3 will be denoted by the same referencesymbols and detailed description of them will be omitted.

FIG. 4 shows a configuration view of an endoscope distal end section. Acover glass 35 is formed of a glass member. The cover glass 35 transmitsvisible light and laser light Q. A laser absorbing member 40 is providedbetween the cover glass 35 and a light guide fiber bundle 33. The laserabsorbing member 40 is formed of a thermoplastic resin that absorbslaser light Q. Incidentally, a surface of the cover glass 35 in contactwith the laser absorbing member 40 may be formed into, for example, anaventurine surface having a plurality of small spots.

Laser light Q is applied to the cover glass 35 from the outside thereof.The laser light Q is transmitted through the cover glass 35, and isapplied to the laser absorbing member 40. As a result of this, the laserabsorbing member 40 is heated and melted, thereby welding the coverglass 35 and the light guide fiber bundle 33 together. Incidentally, ifthe surface of the cover glass 35 in contact with the laser absorbingmember 40 is formed into, for example, an aventurine surface having aplurality of small spots, the bond between the cover glass 35 and thelight guide fiber bundle 33 becomes firm.

As described above, according to the fourth embodiment, the laserabsorbing member 40 is provided between the cover glass 35 and the lightguide fiber bundle 33, the laser light Q is applied to the laserabsorbing member 40, thereby heating and melting the laser absorbingmember 40, and welding the cover glass 35 and the light guide fiberbundle 33 together. As a result of this, even in a small-sized endoscopedistal end section, the cover glass 35 and the pipe sleeve 34 can bereliably welded together.

Next, a fifth embodiment of the present invention will be describedbelow with reference to the accompanying drawings. Incidentally, thesame parts as those in FIG. 3 will be denoted by the same referencesymbols and detailed description of them will be omitted.

FIG. 5 shows a configuration view of an endoscope distal end section. Adistal end constituent member 31 is formed of a thermoplastic resinmember that absorbs laser light Q. The distal end constituent member 31is provided with a tapered opening section 50. The tapered openingsection 50 is formed into a tapered shape that spreads out from the sideon which the light guide fiber bundle 33 is provided toward the openedside. A caliber of the tapered opening section 50 is formed larger thana diameter of the light guide fiber bundle 33.

A cover glass 35 is provided in the tapered opening section 50. Thecover glass 35 can have a diameter larger than that of the cover glass35 used in FIG. 3 or 4. A surface of the cover glass 35 in contact withthe tapered opening section 50 is formed into an inclined (tapered)surface that can be fitted in the tapered shape of the tapered openingsection 50. The cover glass 35 is formed of a light-transmitting resinmember that transmits visible light and laser light.

When laser light Q is applied from the outside of the cover glass 35,the laser light Q is transmitted through the cover glass 35, and isapplied to an abutment part between the cover glass 35 and the taperedopening section 50 of the distal end constituent member 31. As a resultof this, the cover glass 35 and the tapered opening section 50 areheated and melted, thereby welding the cover glass 35 and the taperedopening section 50 together.

As described above, according to the fifth embodiment, the distal endconstituent member 31 is provided with the tapered opening section 50,and the cover glass 35 is welded to the tapered opening section 50. As aresult of this, even in a small-sized endoscope distal end section, thecover glass 35 can be reliably welded to the tapered opening section 50.

Incidentally, the third to fifth embodiments described above are notlimited to the light guide part of the endoscope, and can also beapplied to an image guide.

Next, a sixth embodiment of the present invention will be describedbelow with reference to the accompanying drawings.

FIG. 6 shows a configuration view of an insertion section distal end ofan electronic endoscope. The electronic endoscope insertion sectiondistal end is constituted of a distal end constituent section formed ofa hard member and a distal end insulating cover for covering the distalend constituent section. Of these members, the distal end constituentsection is formed of a metallic member or the like, and is formed into asubstantially pillar-like shape.

The distal end constituent section includes an imaging unit formed byintegrating a first unit 60 and a second unit 61 into one unit. In thefirst unit 60, an objective lens 63 which is arranged at the front end,and is constituted of a plurality of optical systems is arranged in alens frame 64 which is a first frame body, whereby an objective unit isformed.

The second unit 61 is provided behind the first unit 60. The second unit61 includes an imaging section 65 for imaging an image made incidentthereon through the objective unit. The imaging section 65 is formed byarranging a CCD chip 66, a first cover glass 67, a second cover glass68, and the like. In the second unit 61, a channel hole or the like forarranging a forceps channel member is formed. The forceps channel memberconstitutes a unit insertion hole, and treatment tool insertion channel.In the unit insertion hole, the imaging unit 62 is arranged. In thetreatment tool insertion channel, a treatment tool such as biopsyforceps or the like is inserted.

The second unit 61 includes a CCD holder 69 which is a second framebody. The CCD holder 69 is fitted on the rear side of the lens frame 64of the first unit 60. The CCD holder 69 is provided on a front endsurface of the imaging section 65. By fitting the CCD holder 69 on thelens frame 64, the first unit 60 and the second unit 61 are integratedinto one unit, i.e., the imaging unit 62.

The objective lens 63 includes a lens 70. The lens 70 is formed of aresin member. The lens frame 64 is formed of a resin member.Accordingly, both the lens 70 and the lens frame 64 are constituted of acombination of resin members.

A resin member 71, which is a laser light absorbing member, is providedbetween the lens 70 and the lens frame 64.

When laser light Q is applied from the outside of the objective lens 63,the laser light Q is transmitted through the lens 70 of the objectivelens 63, and is applied to the resin member 71 provided between the lens70 and the lens frame 64. As a result of this, the lens 70 and the lensframe 64 are welded together by the melted resin member 71.

Incidentally, each of a surface of the lens 70 and a surface of the lensframe 64 which are in contact with the resin member 71 may be formedinto, for example, an aventurine surface having a plurality of smallspots. This makes the bond between the lens 70 and the lens frame 64firm.

As described above, according to the sixth embodiment, the resin member71 is provided between the lens 70 and the lens frame 64, the resinmember 71 is irradiated with the laser light Q, thereby welding the lens70 and the lens frame 64 together by the thus melted resin member 71. Asa result of this, even in a small-sized insertion section distal end ofan electronic endoscope, the lens 70 and the lens frame 64 can bereliably welded together.

The above description has been given of an example in which the resinmember 71 is provided and, if the lens frame 64 is formed of a laserlight absorbing member, the resin member 71 may be omitted.

1. A capsule endoscope comprising: a first exterior member formed of anoptical resin member transmitting visible light and laser light; and asecond exterior member which is arranged with respect to the firstexterior member in such a manner that the second exterior member isbrought into surface contact with the first exterior member, and isformed of a resin member containing a laser light absorbing agent,wherein laser light is applied to the second exterior member through thefirst exterior member, thereby melting the second exterior member, andthe first exterior member and the second exterior member are bonded toeach other by laser welding.
 2. A capsule endoscope comprising: a firstexterior member formed of an optical resin member transmitting visiblelight and laser light; a second exterior member which is arranged withrespect to the first exterior member in such a manner that the secondexterior member is brought into surface contact with the first exteriormember, and is formed of a resin member; and a laser light absorbingmember provided at a part at which the first exterior member and thesecond exterior member are in surface contact with each other, whereinlaser light is applied to the laser light absorbing member through thefirst exterior member, thereby melting the laser light absorbing member,and the first exterior member and the second exterior member are bondedto each other by laser welding.
 3. The capsule endoscope according toclaim 1 or 2, wherein a capsule endoscope casing formed by bonding thefirst exterior member and the second exterior member to each other isformed into a cylindrical shape, and a bonded part at which the firstexterior member and the second exterior member are bonded to each otheris provided on the entire circumference of a side surface of the capsuleendoscope.
 4. The capsule endoscope according to claim 1 or 2, whereinin a bonded part at which the first exterior member and the secondexterior member are bonded to each other, the second exterior member isfitted into the first exterior member, the first exterior member beingon the outside, and the second exterior member being on the inside. 5.The capsule endoscope according to claim 1 or 2, further comprising: afirst opening end section formed in the first exterior member; and asecond opening end section formed in the second exterior member, whereinin a bonded part at which the first exterior member and the secondexterior member are bonded to each other, the second opening end sectionis inserted/fitted into the first opening end section, and at a boundarysurface between the first opening end section and the second opening endsection, the first opening end section and the second opening endsection are integrally and tightly fixed to each other by weldingachieved by laser light irradiation.
 6. The capsule endoscope accordingto claim 5, wherein the bonded part at which the first exterior memberand the second exterior member are bonded to each other includes afitting surface at which the first opening end section and the secondopening end section are in surface contact with each other, and ahitting surface at which the first opening end section and the secondopening end section hit against each other, and is formed by weldingachieved by irradiating at least one of the fitting surface and thehitting surface with the laser light.
 7. The capsule endoscope accordingto claim 1 or 2, wherein the second exterior member is formed of athermoplastic resin member.
 8. The capsule endoscope according to claim1 or 2, wherein the second exterior member contains a coloring member.9. The capsule endoscope according to claim 2, wherein the laser lightabsorbing member is provided on an inner wall surface of the firstexterior member.
 10. The capsule endoscope according to claim 2, whereinthe laser light absorbing member is provided on an outer wall surface ofthe second exterior member.
 11. The capsule endoscope according to claim1 or 2, wherein the laser light is provided with a transmissivity equalto 26% or more with respect to the first exterior member.
 12. Thecapsule endoscope according to claim 1 or 2, further comprising aprotection member which is provided at a fitting section at which theend section of the second exterior member is fitted into the end sectionof the first exterior member, and absorbs at least the laser light. 13.The capsule endoscope according to claim 3, further comprising aprotection member which is provided at a fitting section at which theend section of the second exterior member is fitted into the end sectionof the first exterior member, and absorbs at least the laser light. 14.A method of manufacturing a capsule endoscope comprising: arranging asecond exterior member formed of a resin member containing a laser lightabsorbing agent with respect to a first exterior member formed of anoptical resin member transmitting visible light and laser light in sucha manner that the second exterior member is brought into surface contactwith the first exterior member; and applying laser light to the secondexterior member through the first exterior member, thereby melting thesecond exterior member, and bonding the first exterior member and thesecond exterior member to each other by laser welding.
 15. A method ofmanufacturing a capsule endoscope comprising: arranging a secondexterior member formed of a resin member with respect to a firstexterior member formed of an optical resin member transmitting visiblelight and laser light in such a manner that the second exterior memberis brought into surface contact with the first exterior member;providing a laser light absorbing member at a part at which the firstexterior member and the second exterior member are in surface contactwith each other; and applying laser light to the laser light absorbingmember through the first exterior member, thereby melting the laserlight absorbing member, and bonding the first exterior member and thesecond exterior member to each other by laser welding.